Oxygen 101

[akarilo]

After installing an AFR meter on the recent turbo install, I noticed that:

A. The O2 sensor took too long to heat up.
B. The gauge reading was reluctant to show much activity.
C. At cruising speed on the highway, (-5 to 0 vacume), The gauge
was stagnant in the rich zone.

On a few previous turbo installs, I noticed the gauge was allways "interpolating" (moving) from zone to zone. I assume this is a result of the fuel trimming that is carried out by the combo of the O2/ECU.

I also noticed my gas tank was emptying quicker than I could fill it up, NORMAL WITHOUT THE TURBO!

I installed a Bosch 4 wire, and wired both sets of wires into the same sensor, (previously debated on this site), and it works phenominal. I now have rapid movement from the sensor and it is "interpolating" at cruise which saves a ton of fuel.

Don't have mileage figures, but I took a short trip today that I frequantly make, and it didn't make near the dent in my fuel gauge reading that it usually does.

Long story short, if you even think your O2 is in the "marginal" zone, I would highly recommend a new one, (or two), if you must.

 

[weak-link]

can't wait to see some mpg readings with the turbo

 

[donphillipe]

I just picked up 2 Bosch 15730 for my '90 FJ62. Is this the right one? Any tips on installing? I looked at the mounts with a quick slide underneath. They look like they are rusted over. Any tips?

 

[PabloCruise]

Is stock 2-wire? What do you hook the other wires to?

 

[donphillipe]

I am trying to fix a rough idle problem and 12MPG highway "problem". I see where others have fixed similar problems with new O2 sensors.

To being with, I did some searching on "O2" and "oxygen sensors" on this forum and read where someone said those 2 devices before my 2 cat converters are temperature sensors and not O2 sensors? Is this right?

Where I got started was walking into an auto parts store and asking for a fuel filter and all aplicable O2 sensors for this vehicle ('90 FJ62). They said it needed 2 sensors, the guy behind the counter and I slid under the botton and visually saw what looked like O2 sensors mounted just in front of the cat converters. However after finding the other link, I am worried that these aren't what is needed. I am also worried that where these connect is so rusty, if I try to replace them, the CAT converter will crumble under my wrenching strong arm.

 

[PabloCruise]

Bump this back up:

1) How do you wire a 4 wire into a 2 wire system?
2) What is the data re running 1 o2 sensor vs. 2?
3) Updates on this specific install?

 

[lehiguy]

Bump this back up:

1) How do you wire a 4 wire into a 2 wire system?
2) What is the data re running 1 o2 sensor vs. 2?
3) Updates on this specific install?

A one-wire is a narrow band, non-heated O2 sensor. A three-wire is a narrow band heated (one lead is hot the other ground and they are not polarized) a four-wire is a wide band heated sensor. Usually if a vehicle has more than one (my Bimmer had four) one is pre cat and the other post cat. This tells the car if the cats are scrubbing the exhuast as they should be.

 

[Mace]

A one-wire is a narrow band, non-heated O2 sensor. A three-wire is a narrow band heated (one lead is hot the other ground and they are not polarized) a four-wire is a wide band heated sensor. Usually if a vehicle has more than one (my Bimmer had four) one is pre cat and the other post cat. This tells the car if the cats are scrubbing the exhuast as they should be.

not always, there are lots of narrow band 4 wire, heated sensors out there. The 4th wire is just a dedicated ground for the sensor itself.

5 or more wires typically mean that it is a wideband setup. 4 can be either.

On a 62 the dual sensors were each on a set of three cylinders. Not before/after the cat..

1) There is no good reason to try to wire a 4 wire system into a 2 wire setup. You just have to make sure that the location of the )2 sensor gets enough heat..
2) It has been speculated that you will get improved performance/economy. I have not seen how it would make that much difference tho..

 

[alkaline747trio]

I'm lost here myself. Akarilo is claiming better mileage and better O2 performance, Mace is saying this shouldn't be true. What's the difference? How do you hook up a wide-band sensor to a 3FE? Does a wideband O2 allow the use of an AFR meter?

 

[Mace]

No, I said that there is no reason to swap to the 4 wire as long az the 2 wire was in the right place.

 

[ntsqd]

The only gain that I see in a 4 wire is that it is heated, so it will "light off" quicker than a 2 wire sensor and stay lit during those odd times when the running conditions result in a low exhaust gas temperature.

Unless you're the EPA or extremely concerned about emissions during warm-up I don't see much advantage to this splitting of hairs.